PEAR GROWING IN CALIFORNIA. 



345 



While all the symptoms given are valuable in the detection of pear 

 blight the experts, who are trained for the work of control are able to 

 pick out obscure cases some time before death takes place and before 

 there is a marked discoloration. The first symptoms are wilting of 

 the foliage of a diseased twig, bark slightly discolored or blackened in 



FIG. 145. Blighted pear twigs. Note the beads of gum in front of arrow. 



spots, an abundant flow of sap which may already have oozed from the 

 twig, and a discolored cambium as described. 



Holdover blight either above or below ground may be detected by 

 the presence of dead, more or less sunken, areas of brown and black- 

 ened bark. The discoloration of the cambium in such cases may 

 readily be seen extending back for a short distance beyond the dead 



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